CATALOGUE. 259 what I have seen under that name, is a true Cembra, not to be thrown together with P. pygmcea, as has been done, and distinguished from Cembra itself by the denticulate Strobus-Vike leaf-tips. 3. Eustrobi, with distinctly winged seeds, leaves sharply serrulate on the edges and generally denticu¬ late aU over the tip, mostly without stomata on the back, and with periph¬ eral ducts, like the last. Of this subsection we have P. Strobus, monticola, and Lambertiana; Mexico has P. Ayacahuite; Japan, P. parviflora; the East Indies and Turkey, P. excelsa with P. Peuce. Pinus monophyllos, Torr. & Frem. Report Expl. Exped. 1842-1844, p. 319, t 4; Parlat. I. c. 378.—A small tree, of scraggy growth, with gray bark and stout, mostly single,* terete leaves' (rarely in pairs, and then semicylindrical and entire on the margins), 1^-2' long, ^1" thick or wide, with a deciduous sheath; involucre of the staminate flowers of about 6 scales; anthers with a short, entire or denticulate knob; cones subterminal, ovate-subglobose, 2 or 2 J' long and nearly as thick, consisting of few large scales with thick pyramidal apophyses, but without prickles; oval seeds about .^' long, with a wing nearly 1" wide; cotyledons 7-10. The oft-described Nut-pine of Fremont's first expeditions, 35 years ago, common from Arizona to Utah and California. This and the follow¬ ing species furnish an important article of food to the Indians and other natives. That single leaf, before its nature was properly understood, troubled botanists a good deal, so that Endlicher, supposing that the single leaf con¬ sisted of two agglutinated ones, went so far as to change the name into P. Eremontii. They are really single leaves, and the only instance of such leaves in-the genus (I do not speak of the primarj'^ leaves of seedlings or young shoots, but only of the secondary leaves, which grow in bundles on what we must take for reduced branchlets). * The fresh leaves of pines, when single, are terete, and when dry, become grooved and ridged; the leaves which grow in pairs are semiterete, flat on the upper or inner, and convex on the lower or outer side, and only when (on the tree as well as still more in the herbarium) they become dry, they assume that channelled form which we find so often described as characteristic of a species; those leaves that grow in hundles of 3 or 5 are convex on the dorsal and ridged on the upper side; those with 3 are flattish, about half as thick as wide; those with 5 are triangular and nearly as thick as wide. It is therefore superfluous to minutely describe the form of the leaves, as that is already given when the number within the sheath is stated, nor is it proper to describe the dried and shrivelled condition. The serra¬ tures, their closeness, the Size of the minute teeth or their absence (only in a few Western American species the edges of the leaves are without teeth) are of much greater importance, and to some extent the nature of the tip is also of value.